The principal objective of this proposal is to characterize both existing and newly synthesized plasma membrane components of mouse Sertoli cells during development. This will be accomplished by undertaking an integrated series of biochemical, immunological and morphological analyses of membrane constituents of Sertoli cells isolated from normal and SCE enriched testes at discreet intervals in the development process. Experimentation will be directed initially toward a detailed characterization of the recovery, attachment and adhesion phases of prepuberal Sertoli cells in culture. Homogenous and monodisperse preparations of Sertoli cells at Day 6 of development can be obtained for this purpose. Synthesis of plasma membrane focosyl-glycoproteins during these three phases will be examined using dual isotope technology with isotopic fucose as a precursor. Existing plasma membrane proteins, as opposed to those synthesized, will be studied by using the dual-labeled isotopes of sulfanilic acid. Plasma membrane fractions will be isolated and the isotopically-labeled glycoprotein and protein constituents characterized by SDS-polyacrylamide gel electrophoresis. This effects of the hormones, FSH and testosterone, and also analogues of 3',5', cyclic AMP, on the synthesis of plasma membrane constituents will be correlated with their influence on Sertoli cell morphology. Heterologous antibodies, prepared against specific membrane constituents, will be used to topographically localize the antigens on the cell surface. It is anticipated that these studies will enable the identification of specific membrane constituents of Sertoli cells, and potentially could resolve their physiological function in the reproductive biology of mammalian spermatogenesis.